In an interchangeable lens removably mounted on the body of a camera, there is a system in which information concerning the direction of lens movement and size of lens aperture is transmitted upon being changed over on a single signal line in order to avoid an increase in lens contacts (Patent Document 1). Further, there is a system which, in a case where the main body of a camera transmits a control signal so as to cause an interchangeable lens to execute operations one by one, multiple movable members are driven simultaneously because completion of processing would take a long period of time (Patent Document 2). Furthermore, there is a technique in which a real-time property is assured in a microprocessor system by using exclusive control (Patent Document 3). In addition, there is a system that prevents the intrusion of noise due to power inadequacy in a television lens apparatus (Patent Document 4).    [Patent Document 1]: Japanese Patent Application Laid-Open No. 2011-112700    [Patent Document 2]: Japanese Patent Application Laid-Open No. 2010-15131    [Patent Document 3]: Japanese Patent Application Laid-Open No. 2010-140290    [Patent Document 4]: Japanese Patent Application Laid-Open No. 7-99599
Consider implementation of camera control using multiple camera control boards which are independent of one another and which are connected together by network lines. In such case communication data will collide on a network line if the multiple camera control boards communicate using the network line at the same time. In all cameras and the like, however, collision of communication data on a network line is not taken into account because no consideration is given to execution of camera control using multiple camera control boards connected together by a network line.